Timing device



June 19, 1951 T, R, ARDEN 2,557,626

TIMING DEVICE Filed Jan. 16, 1948 Patented June 19, 1951 TIMING DEVICE Thomas Raymond Arden, Danbury, Conn., as-

signor to Bard-Parker Company, Inc., Danbury, Conn, a corporation of New York Application January 16, 1948, Serial No. 2,752

This invention relates to timing devices, and has particular reference to a timing device which is especially intended and designed to automatically stop the operation of model airplane engines to predetermine and limit the time periods during which the airplanes are powered in their flights. The present timer may, however, readily be adapted to perform other timing purposes.

One reason for limiting the duration of powered flights of model airplanes is to avoid flying of the same long distances from their launching points and becoming lost. More importantly, however, in model airplane contests, flights for records and the like, the airplanes usually are flown against time rather than against one another, and a basic factor in determining and comparing their performances is the time during which they are powered in flight. It is important, therefore, to'provide a timing device by means of which the time during which model airplanes are powered in their flights may be predetermined very accurately.

Accordingly, one special and important object of the present invention is to provide a timing device which is thoroughly reliable in operation to predetermine accurately the length of time during which a model airplane is powered in its flight.

Another special and important object of the invention is to provide a timing device which may readily and easily be adjusted to vary the amount of time during which it operates to perform its function, thereby to variably predetermine the time periods of events which it controls, as, for example, the time period during which a model airplane is powered in its flight.

5 Claims. (Cl. 123-73) Another special and important object of the invention is to provide a timing device which completes its operation with a snap action whereby it is rendered very accurate in the performance of its timing purpose.

The present timing device may be designed to open the ignition circuit of an engine to stop the same. However, many engines now are being operated without spark ignition. Moreover, most model airplane engines are of the two-stroke cycle type. Accordingly, another special and important object of the invention is to provide a timing device which is effective to vent the crank cases of engines of the two-stroke cycle type to stop the same, whereby it may be used in connection with such engines regardless of whether their operation is or is not dependent upon spark ignition.

Another special and important object of the invention is to provide a timing device which may readily and easily be applied to an engine and which is readily and easily adjustable to dispose a control handle thereof for most convenient access in any particular instance.

Another special and important object of the invention is to provide a simple, practical, reliable timing device of the cylinder and piston, pneumatic type.

With the foregoing and other objects in view, which will become more fully apparent as the nature of the invention is better understood, the same consists in a timing device embodying the novel features of construction, combination and arrangement of parts as are illustrated by way of example in the accompanying drawings and as will be hereinafter more fully described and claimed.

In the accompanying drawings, wherein like characters of reference denote corresponding parts in the different views:

Figure 1 is a longitudinal section through a timing device constructed in accordance with the invention and shown as operatively applied to a model airplane engine;

Figure 2 is a top plan view of the assembly shown in Figure 1;

Figure 3 is an enlarged longitudinal section through the inner end portion of the timer; and

Figure 4 is a cross section on the line l-A of Figure 3.

Referring to the drawings in detail, A designates, generally, a timing device constructed in accordance with the present invention, and B designates, generally, a model airplane engine of a type with which said timing device is designed for use.

The engine B is of 'the two-stroke cycle type characterized by drawing of explosive charges into its crank case In by outward movements of its piston l l, and by compression of the explosive charges in said crank case and forcing of the same from the latter into the cylinder I2 by inward or power strokes of the piston II. If the engine is operating, venting of its crankcase I!) will result in its immediate stoppage for obvious, Well-known reasons.

The purpose of the timer A is to vent the crank case N3 of the engine B and thereby stop the latter after a predetermined period of operation of the same beginning with initiation of operation of the timer.

The timer A comprises a cylinder l3 of suitable diameter and length, closed at its outer end, asindicated at I4, and having slidable therein 3 a timer piston I5. In said cylinder, between its closed outer end I4 and the piston I5, is an expansion coil spring I6 which tends constantly to slide said piston toward the inner end of said cylinder.

Projecting outwardly from the closed outer end I4 of the cylinder I3 is an exteriorly threaded nipple I1 through which extends a small axial bore I8 for the admission of atmospheric air to the outer end portion of said cylinder, while threaded on said nipple is a cap I9 which has axially mounted therein a needle valve 20 for cooperation with said bore I8 to vary the effective area thereof by screwing of said cap inwardly or outwardly on said nipple. In the side wall of said cap I9 is an opening 2| which affords communication between the atmosphere and the interior of said cap and, hence, between the atmosphere and the bore I3, under the control of the needle valve 26. On the nipple I1 is threaded a lock nut 22 for cooperation with the inner end of the cap I9 to secure the latter in any desired adjusted position on said nipple.

Inward movement of the timer piston l in the cylinder I3 by the spring I6 produces in said cylinder, between its closed outer end and said piston, sub-atmospheric pressure which resists inward movement of said piston. Consequently, the amount of atmospheric air which is admitted to the cylinder I3 through the bore I8 of the nippe I1 determines the rate of inward movement of the piston I5 in said cylinder by the spring I6. In other words, by adjustment of the needle valve 20, the time required for the spring IE to move the piston I5 a given distance inwardly through the cylinder I3 may accurately be predetermined.

Over the inner end portion of the cylinder I3 is engaged a plug member 23 which is closed at its inner end by a wall 24 and which therefore serves as a closure for the inner end of said cylinder. The cylinder I3, near its inner end, is provided with an exterior, annular rib 25, and said plug member, outwardly of its inner end closing wall 24, is provided with a bore the inner end portion of which is of a diameter to neatly accommodate the inner end portion of the cylinder I3 and the outer end portion of which is of sufficiently greater diameter than its inner end portion to accommodate the rib 25 of said cylinder and to provide, at its inner end, an outwardly facing shoulder 25 against which the inner side of said rib abuts. Surrounding the cylinder l3 outwardly of the rib 25 and threaded in the outer end portion of the plug member 23, is a collar 21 the inner end of which is engageable with the outer side of the rib 25. Accordingly, by loosening said collar 21, the cylinder I3 may be rotatably adjusted relative to the plug member 23, while by tightening said collar said cylinder may be firmly secured to said plug memher in any position of rotative adjustment of the same relative to said plug member.

In the inner end of the wall 24 is a central recess 28 in which is disposed a valve 29 of the poppet type which is designed to seat marginally against the rear face of said wall 24 at the bottom of said recess 28 and which is for the purpose of controlling flow of air through one or more parts 30 extending through said wall 24. A stem 3| extends outwardly from the valve 29 through a guide 32 constituting part of the plug member 23 and at its front end is exposed, in.

said plug member and is equipped with a suitable head 33 between which and the front face of the wall 24 of said plug member is interposed an expansion helical spring 34 which tends constantly to urge said valve forwardly to a closed position denying flow of air through the port or ports 30. The guide 32 constitutes a stop, engageable by the head 32, to limit rearward as opening movement of the valve 29, and when said valve isfully open, as shown in Figure 3 of the drawings, no part of the same projects inwardly beyond the inner face of the wall 24 of the plug member 23.

Extending inwardly from the piston I5 is a rod 35 the inner end of which is engageable with the outer end of the valve stem 3| to move the valve 29 inwardly to its open position upon completion of a predetermined amount of inward movement of the piston 55 by the spring I6 from a starting position of said piston.

The rod 35, near its inner end, is provided with a supporting and guiding crosshead 36, while in the side wall of the cylinder I3 is an elongated slot 31 which extends longitudinally of said cylinder and which, at its outer end, is continued laterally or offset as indicated at 38.

A handle 39 is threadedly or otherwise suitably connected at its inner end to the crosshead 36 and extends through the slot 31 exterior-1y Of the cylinder I3 for ready access and finger engagement to shift the piston I5 outwardly to a starting position in the cylinder I3 near the outer end of the latter.

The slot 31 is disposed relative to the cylinder I3 so that when the piston I5 is in its starting position illustrated in Figure 1 of the drawings, the handle 39 is disposed at the outer end of said slot. Accordingly, the piston I5 may be releasably retained or latched in its starting position simply by slightly swinging the handle 39 laterally to engage the same in the lateral continuation or offset 38 of the slot 31 at the outer end of the latter. Likewise, the piston I5 may be released for inward movement by the spring I 6 simply by slightly swinging the handle 39 laterally to disengage the same from the lateral continuation or offset 38 of the slot 31 and to aline it with said slot 31.

In the side wall of the cylinder I3 is an open-' ing 40 which is located at a point to be passed and uncovered by the piston l5 to freely vent the cylinder space between the outer end of the latter and said piston I5 when, during inward movement of said piston, the inner end of the rod 35 has reached a position more or less closely adjacent to the outer end of the valve stem 3|. When the outer end portion of the cylinder I3 is vented through the opening 43, the spring I6 is free to move the piston I5 rapidly inward. Consequently, the final or valve-opening portion of inward movement of the piston I5 occurs rapidly or, in other words, instantaneously with a snap action. Therefore, the valve 29 is opened instantaneously with a snap action. Therefore, the valve 29 is opened instantaneously rather than gradually, which measurably contributes to rendering it possible to predetermine accurately, by adjustment of the needle valve 28, the time required for the timer to perform its function of opening the valve 29 beginning with release of the piston I5 for inward movement from its outer or starting position.

In the rear wall of the crank case I0 of the engine B is an opening through which access isafforded to said crank case and which ordinarily is closed by a threaded plug. To apply the present timer to said engine, the said threaded plug simply is removed and is replaced by the plu member 23, the inner end portion of which is of a size and is exteriorly threaded to be readily screwed into said crank case opening. Since the valve 29 always is disposed within the recess 28, it cannot, when opened, interfere with the crank or any other part of the engine.

When the timer A has been applied to the engine B, it is obvious that as long as the piston iii of the timer is held in its outer or starting position, the valve 29 will be maintained closed by its spring 34 and the engine crank case will not be vented. Consequently, as long as the timer piston is held in its outer or starting position, the engine may be operated. However, upon release of the timer piston forinward movement by the spring it, the valve 29 will be opened and the engine crank case will be vented through the port or ports 3%, with consequent automatic stopping of the engine, upon the elapse of a predetermined period of time corresponding to the time required for inward movement of the timer piston from its starting position to the position in which its rod 35 effects opening of the valve 29.

Obviously, should it be desired to employ the present timer to stop an engine of the spark ignition type by opening of the ignition circuit, the valve 29 may be replaced by a normally closed electric switch controlling the ignition circuit and openable in the same manner as the valve 29.

The provision for rotative adjustment of the timer cylinder I3 relative to the plug member 23 and hence for adjustments of the timer handle 39 to any desired angular position relative to a model airplane in which the timer maybe installed, is to enable said handle to be disposed in a position for most convenient access and manipulation. In this connection and in order to enable ready and easy loosening of the collar 21 to permit such adjustments and subsequent tightening of said collar to maintain any desired adjustment made, said collar may be provided at its outer end with an exteriorly knurled flange 4| for finger engagement.

As will be understood, with the engine B operating and the timer piston He held in its starting position by the handle 39, said handle may be swung at any time to release the piston [5 for inward movement, by the spring, it, as when the airplane is released for flight, and thereafter the engine will be automatically stopped by opening of the valve 29 after a period of time predetermined by adjustment of the needle valve 28 to regulate the rate of inward movement of the piston l5, thus predetermining the time during which flight of the airplane is powered by the engine B.

While the present timer has been described as designed for the particular purpose of controlling the time periods of powered flights of model airplanes, it manifestly is not limited to this use, but may be used for any similar purpose such as controlling the time periods during which power is supplied to to land vehicles, boats and the like.

Moreover, while only a single, specific structural embodiment of the present timer has been illustrated and described, it is desired to point out that the same may be modified in various different respects within the spirit and scope of the invention as defined in the appended claims.

I claim:

1. A timing device comprising a, cylinder closed at its outer end, a piston in said cylinder, yieldable means for moving said piston in said cylinder away from the closed end thereof, releasable means for holding said piston in a starting position in said cylinder, valve means to vent said cylinder between its closed end and said piston to predetermine the amount of time required for movement of said piston a given distance in said cylinder from its starting position by said yieldable means, a closure for the inner end of said cylinder engageable in an opening in a wall of the crank case of an internal combustion engine, a normally closed valve carried by said closure and operable when opened to vent said crank case and thus stop the engine, and means whereby said piston is effective to open said valve at the end of a predetermined amount of movement of said piston from its starting position by said yieldable means.

2. A timing device as set forth in claim 1 in which the cylinder is provided with a vent opening to be uncovered by the piston as the latter approaches the end of its movement in the cylinder under the influence of the yieldable means, thus to freely vent the cylinder between its outer end and the piston to permit rapid final valveopening movement of the piston.

3. A timing device comprising a cylinder closed at its outer end and having an external shoulder adjacent to its inner end, a piston in said cylinder, yieldable means for moving said piston in said cylinder away from the closed end thereof, releasable means for holding said piston in a starting position in said cylinder, valve means to vent said cylinder between its closed end and said piston to predetermine the amount of time required for movement of said piston a given distance in said cylinder from its starting position by said yieldable means, a closure for the inner end of said cylinder engageable in an opening in a wall of the crank case of an internal combustion engine, a normally closed valve carried by said closure and operable when opened to vent said crank case and thus stop the engine, means whereby said piston is effective to open said valve at the end of a predetermined amount of movement of said piston from its starting position by said yieldable means, said cylinder having therein an elongated slot extending longitudinall thereof and provided with a lateral offset, a handle extending from said piston through said slot for moving said piston outwardly in said cylinder to its starting position, said handle being engageable in the lateral ofiset of said slot to releasably hold said piston in its starting position said cylinder being rotatably mounted at its inner end in said closure to vary the angular position of said handle relative to the engine, and a nut on said cylinder engageable with the shoulder of the latter and having threaded connection with said closure for securing said cylinder in any desired position of rotation relative to said closure.

4. A timing device comprising a cylinder closed at its outer end, a piston in said cylinder, yieldable means for moving said piston in said cylinder away from the closed end thereof, releasable means for holding said piston in a starting position in said cylinder, valve means to vent said cylinder between its closed end and said piston to predetermine the amount of time required for movement of said piston a given distance in said cylinder from its starting position by said yieldable means, a closure for the inner end of said cylinder engageable in an opening in a wall of a device to be vented and having therein a vent port, a valve carried b said closure and normally closing said vent port, and means whereby said piston is effective to open said valve at the end of a predetermined amount of movement of said piston from its starting position by said yieldable means.

5. A timing device comprising a cylinder closed at its outer end and having an external shoulder adjacent to its inner end, a piston in said cylinder, yieldable means for moving said piston in said cylinder away from the closed end thereof, releasable means for holding said piston in a starting position in said cylinder, valve means to vent said cylinder between its closed end and said piston to predetermine the amount of time required for movement of said piston a given distance in said cylinder from its starting position by said yieldable means, a closure for the inner end of said cylinder engageable in an opening in a wall of a device to be vented and having a vent port therein, a valve carried by said closure and normally closing said vent port, means whereby said piston is effective to open said valve at the end of a predetermined amount of movement of said piston from its starting position by REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 783,024 Cox, Jr Feb. 21, 1905 884,853 Radcliffe Apr. 14, 1908 914,366 Willet Mar. 2, 1909 1,040,712 Lutenegger Oct. 8, 1912 1,104,118 Holtfoth July 21, 1914 1,227,991 Barnett May 29, 1917 2,107,388 Purpura Feb. 8, 1938 

